I heard a theory which predicts that the human race will evolve into more empathetic souls partly as a result of the fact that we are writing and expressing our thoughts and feelings with two hands (in keyboarding) because two-handed expressiveness engages both brain hemispheres (rationality and emotionality) rather than using one hand, as in penmanship, which tended to engage only the rational and more dominant brain/handedness.

(I realize that I shifted the topic a bit, since many of the people who commented in this thread are talking about doing cryptos with only one hand on the keyboard. I just wanted to mention an idea about the long-range implications of two-handed self-expression. I find the idea fascinating.)